Currently, Sensei's Library has a way to make breaks that are basically <br clear="all">, ie they are line break that clear everything until they are passed any images/blocks on both the left and the right. This is done with %%%%

Could a markup be added for line breaks that only break left (or right), ie <br clear="left"> and <br clear="right">. Something like %%<%% and %%>%% or so.

See, for example, Grappling Hook Tesuji, where I've used several normal line breaks %%% to put the table of contents under the first diagram. Using %%%% would have put it under the image as well, creating useless whitespace. So the option of %%<%% would've been nice.